fix!: BREAKING CHANGE: vector_store: search API response fix (#4080)

# What does this PR do?
- search_query in the vector store search API should be a list,
according to https://github.com/openai/openai-openapi


## Test Plan
modified tests


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* #4086
* __->__ #4080

tests/integration/vector_io/test_openai_vector_stores.py

@@ -350,7 +350,7 @@ def test_openai_vector_store_search_empty(
     assert search_response is not None
     assert hasattr(search_response, "data")
     assert len(search_response.data) == 0  # Empty store should return no results
-    assert search_response.search_query == "test query"
+    assert search_response.search_query == ["test query"]
     assert search_response.has_more is False